The present invention relates to a ceramic board for the apparatuses used in-semiconductor manufacture and/or inspection, such as the hot plate (ceramic heater), static chuck and wafer prover.
In the semiconductor and/or inspection equipment inclusive of the etching and chemical vapor deposition lines, it is conventional to use heaters and wafer provers based on metallic substrates made of stainless steel, aluminum alloy or the like.
However, metallic heaters have drawbacks such as poor temperature control characteristics, great thickness and bulk, and poor corrosion resistance to corrosive gases.
To obviate those drawbacks, heaters based on ceramic boards such as aluminum nitride in lieu of metal substrates have heretofore been developed.
Such ceramic heaters have the advantage that because of the high rigidity of the ceramic board itself, curling of the board, among other troubles, can be precluded without increasing the board thickness too much.
As a technology of this type, Japanese Kokai Publication Hei-11-40330 discloses a heater comprising a heating element disposed on the surface of a nitride ceramic substrate.
Moreover, Japanese Kokai Publication Hei-9-48668 discloses a heater based on blacked aluminum nitride.
However, the experiments performed by the present inventors demonstrated that such aluminum nitrides suffer decreases in Young""s modulus with increasing temperature.
Particularly, it was found that as the temperature rises to 600xc2x0 C., Young""s modulus declines to about 280 GPa. With a declining Young""s modulus, the incidence of curling at high temperature is increased so that wafers cannot be uniformly heated. This tendency is particularly pronounced with large, thin ceramic boards not less than 200 mm in diameter and not more than 25 mm in thickness.
The present invention has for its object to inhibit said decrease in Young""s modulus at high temperature without compromise in various other characteristics such as heat conductivity.
The present invention is directed to a ceramic board for semiconductor manufacture and inspection comprising a conductor layer internally or on the surface thereof
which is composed of nitride ceramics containing oxygen and 0.1 to 50 ppm (wt.) of Si.